The pilot took off in order to take his passenger friend on an airborne tour of the town of Fethard.At between 900 and 1,100 ft, the pilot heard a bang from the rear of the helicopter. He then realised he had no directional controls using the pedals. The pilot autorotated into a grass field and managed to crash land the helicopter.The horizontal stabilizer spar had failed in fatigue, and the departing stabilizer struck the tail rotor resulting in the bang heard by the pilot. There was no fire and both occupants exited the helicopter without injury.The Report makes two Safety Recommendations.